Russia on Tuesday rejected accusations that its forces were responsible for deadly airstrikes on hospitals in northern Syria.

The United Nations said the attacks Monday on medical facilities and schools killed nearly 50 civilians, including children. The Syrian Observatory for Human Rights, which monitors violence in Syria, said the airstrikes were believed to have been carried out by Russian jets.

But Dmitry Peskov, a spokesman for President Vladimir Putin, rejected the accusations and said the Syrian government should be the source of information about who was responsible.

U.N. Secretary-General Ban Ki-moon said "such attacks are a blatant violation of international laws," according to his spokesman.

Syrian rebels blamed President Bashar al-Assad's forces for the strikes that destroyed a 30-bed hospital run by Doctors Without Borders and damaged three other medical facilities in northern Syria.

“This appears to be a deliberate attack on a health structure, and we condemn this attack in the strongest possible terms,” said Massimiliano Rebaudengo, MSF’s Head of Mission. “The destruction of the hospital leaves the local population of around 40,000 people without access to medical services in an active zone of conflict,” Massimiliano said.

Medics and witnesses say at least 10 people were killed at a maternity and pediatric clinic hit by missiles and rockets in the border town of Azaz.

US condemnation

The U.S. State Department condemned the attacks. "We call again on all parties to cease attacks on civilians and take immediate steps to grant humanitarian access and the cessation of hostilities that the Syrian people desperately need," spokesman John Kirby said.

An official with the U.S.-led coalition against Islamic State (Col. Chris Garver) stressed on Twitter there were no coalition aircraft operating near the medical facilities that were attacked.

According to political activists, warplanes also targeted the hospitals in Maret al-Noman and Orem Al-Kubra. Another airstrike in the northern Aleppo countryside left a school sheltering Syrians displaced from other nearby towns seriously damaged with an unknown loss of life, according to Mazin Ibrahim, a relief worker. Another school in the region was also hit, according to the U.N.

As a precaution, staff shuttered the National Hospital Maret al-Noman and a clinic at Mare'.

VOA United Nations correspondent Margaret Besheer contributed to this report